A data preservation problem looms large behind today's information superhighway. All current storage (e.g. paper, magnetic media, silicon chips) media require constant attention to maintain their information content. People or natural disasters can easily destroy all of them intentionally or accidentally. With the large amount of information generated by our society every day, it is time to think of a new generation of data memory.
The use of deoxyribonucleic acid (DNA) as a component of memory storage has been proposed for a number of reasons. For example, DNA as a memory medium is compact. One cubic centimeter of DNA in solution could store 1021 bits of information, whereas, a current conventional computer has a memory of at most 1014 bits. Also, most computers operate linearly, one block of data after another. Biochemical reactions are highly parallel in operation. That is a single biochemical operation can affect trillions of DNA strands in a test tube.
Heller et. al. (U.S. Pat. No. 5,787,032) describe the use of synthetic DNA polymers as an optical storage media for memory. Clelland et. al. reported in Nature (Vol. 399, 10 Jun. 1999, pp. 533–34 or www.nature.com) that encoding meaningful information as DNA sequences is possible. The authors conducted an experiment wherein an encoded DNA strand was hid behind a period (i.e., a dot) of a printed document. The document was then sealed and mailed to its owners using regular US Postal Service. The embedded message was successfully recovered in a lab environment. This work proved that a DNA strand can be a substitute for a piece of paper in terms of information storage. However, a naked DNA molecule can easily be destroyed when exposed to unfavorable environmental conditions such as excessive temperature or dessication/rehydration. Even nucleases in the environment may degrade the DNA molecules over time. Therefore, exploiting DNA as a memory medium would require an effective protective storage medium.
Establishing memory of stored information in a living organism can provide adequate protection for the encoded DNA strands. By providing a living host for the DNA—one that can tolerate the addition of “artificial” gene sequences and survive extreme environmental conditions. Perhaps more importantly, the host needs to be able to grow and multiply with the embedded information. Propagation of a host for memory embodied in DNA can allow for preservation and continuation of the stored memory, as well as protecting the integrity of the information contained in the memory. As well there is opportunity to utilize this capability to store purposeful information.